1. Field of the Invention
The present invention relates to an image pickup apparatus such as an electronic camera, and in particular relates to an image pickup apparatus which prevents dust and the like from sticking to or depositing on a surface or the like of an image pickup device such as a CCD (charge coupled device).
2. Description of the Related Art
Recently, electronic cameras capable of lens exchange have been generally in practical use which comprise a finder device adopting a so-called single lens reflex method and in which a photography optical system is configured detachably from a camera main unit so that a user optionally attaches/detaches the photography optical system and replaces with a desired photography optical system to allow plural kinds of photography optical systems to be selectively used in the single camera main unit. In such electronic cameras, when the photography optical system is detached from the camera main unit, dust and the like floating in the air can enter the camera main unit. In addition, since mechanisms such as a shutter unit and a mirror unit are provided inside the camera main unit, dust may be produced while these mechanisms are operating. Further, when the photography optical system is detached from the camera main unit, a light acceptance surface of an image pickup device disposed in the rear of the photography optical system is exposed to the air inside the camera, so that dust and the like stick to the vicinity of the light acceptance surface of the image pickup device due to factors such as static electricity. Nowadays, such dust having an adverse effect on the pick up of input images is a problem, and various techniques have been proposed to prevent the dust and the like from sticking.
For example, Jpn. Pat. Appln. KOKAI Publication No. 2000-29132 discloses a technique to prevent dust or fuzz from sticking due to electrification of optical members and photoelectric transfer elements provided in an optical path of an optical device. Thus, in this technique, transparent electrodes are provided on a surface of a cover member covering the light acceptance surface of the image pickup device inside the camera, and a direct current voltage or the like is applied to the electrodes, thereby preventing dust and the like from sticking onto the light acceptance surface of the image pickup device due to static electricity.